I would like to suggest a mob. Something for the Nether specifically, and kind of boss like. I'm imagining (as i can't draw, let alone animate...) a monster akin the the Ferrous except larger, and far deadlier. I am thinking something like a Flame Demon, constantly coated in fire so it deals a half heart of damage over time, and switches between smash attacks and swipes (similar to the Ferrous) also having a charged attack, which leaves it open to damage. It would act like an area of effect attack and would do it regularly after 3-4 other attacks. Killing it would drop a weapon that can grant the user a similar Area of Effect attack. As far as overall appearance goes, Lava under a cracked reddish iron armor.
That is my silly and possibly impossible idea. Yay!